There have been employed in the baking of yeast-leavened dough in times past certain chemical agents which have been added to the dough to aid in the production of the finished baked product. The presence of such chemical formulations aided in the production of carbon dioxide during the fermentation procedure as well as improving the overall baking procedure. By reason of such functions, these chemical additives were identified as yeast foods. Such yeast foods have been known for many years and were used as dough additives by bakers as early as 1915, as evidenced by U.S. Pat. No. 1,151,526 issued to Kohman et al. A formula for such a yeast food suggested at this early date is as follows:
Calcium Sulfate: 26.2% PA1 Sodium Chloride: 22.3% PA1 Flour: 41.7% PA1 Ammonium Chloride: 9.5% PA1 Potassium Bromate: 0.26%
The recommended usage of this formulation was about 6.7 ounces per 100 pounds of flour. This formulation was not employed as a concentrate and significantly the potassium bromate in this formulation amounted to about 11 ppm of the flour.
The commercial use of yeast foods has continued from that date and two types of such yeast food have been widely recognized as evidenced by the publication "Baking Science And Technology"--Pyler--Siebel Publishing Co., Chicago, Ill. (1952), Volume 1. Typical formulations identified in the publication as being suitable for use are set forth below with each type being identified by its designated name:
______________________________________ The Arkady Type The Fermaloid Type ______________________________________ Calcium Sulfate 25% Calcium Acid Phosphate 50% Sodium Chloride 25% Sodium Chloride 19.35% Starch 40% Starch 23.43% Ammonium Chloride 9.7% Ammonium Sulfate 7.0% Potassium Bromate .3% Potassium Bromate .12% Potassium Iodate .10% ______________________________________
It will be noted that the bulk of each of the formulations set forth above are relatively inert fillers or diluents as evidenced by the first three ingredients employed in each. These diluents keep the chemically active ingredients in a relatively inactive state and thus such diluted compositions are reasonably stable in storage and conveniently weighable on bakery scales. A baker generally employed about 0.25-0.75% of the composition based on the flour in his baked product formulas or between about four to twelve ounces to a 100 pounds of flour.
The amount of the oxidants employed in each of the two types of yeast food listed above, i.e., the potassium bromate and the potassium bromate plus the potassium iodate, is about 7.5-23.5 ppm of flour. This amount of oxidant is on the same order of magnitude as has been recommended over sixty years ago. This fact thus indicates that the oxidant level is quite small and at relatively critical level although at constant level. The oxidant and the amount employed is therefore associated with the chemistry of the flour and its presence and function has apparently not changed greatly in the intervening years.
In recent years, a yeast food concentrate has been made available to the baking industry in the form of a small package. In this form of use, the package has consisted of a small, water-soluble film packet into which an oxidant, such as potassium bromate, and calcium sulfate, which functions as a scaling agent and which increase the safety factor of the oxidant, have been added and the packet thereafter sealed. The packet is thereafter placed within a larger film packet into which the required ammonium salt and any other desired materials have been placed and the larger packet then sealed. This arrangement produces a single package of a packet within a packet. This procedure thus effectively isolates one active ingredient from the other by physical means and virtually eliminates the need for fillers.
An example of such a "one in one" package that is commercially available is one marketed by J. F. Short Milling Company under the name of "Short Cut". In this package, the amount of total yeast food per 100 lbs. of flour that will be present will be about 23 grams. Thus, the amount used is reduced by a factor of 10. The formula of the so-called "Short Cut" package is as follows:
______________________________________ "Short Cut": (Two packet concentrate) ______________________________________ Ammonium Sulfate 88.4% Calcium Sulfate 8.6% Large Small Packet Packet Potassium Bromate 3.0% ______________________________________
The principal disadvantage with the double package "yeast food" system is that the edible film packets and the sealing and packaging procedures required is rather expensive. Attempts have been made to eliminate such economical disadvantage by preparing concentrates in which the ammonium salts and the oxidizer are placed in intimate admixture in a single package. However, such a unitary combination results in an additive package possessing dangerous instability such that in a relatively short time, such as, for example, about 1-2 weeks the additive package will be unsuitable for use. The reason for such inherent instability of a concentrated mixture of the type noted above appears to reside in the tendency of the ammonium salt to ionize even when in a dry state. This fact results in a conversion of the potassium bromate to ammonium bromate, which is quite unstable, and the salt into potassium chloride or potassium sulfate either of which are stable. The formed ammonium bromate would decompose to yield nitrogen, bromine gas and water, and probably very active intermediate materials. The reaction products seem to catalyze the decomposition, and such decomposition becomes progressively more rapid.
In bulk form, this reaction just described is very dangerous and even in small sealed packets the gas pressures created can rupture the packets and release noxious and corrosive fumes. The following equations explain the reaction that is believed to occur: EQU NH.sub.4 X+KBrO.sub.3 .fwdarw.KX+NH.sub.4 BrO.sub.3 EQU 2NH.sub.4 BrO.sub.3 .fwdarw.N.sub.2 +2HBr+3H.sub.2 O EQU 5HBr+KBrO.sub.3 .fwdarw.KOH+3Br.sub.2 +H.sub.2 O
The interest in the use of concentrated yeast foods by the baking industry in bulk powdered form has been caused by the availability of very accurate mechanical feeders which can be set to deliver a predetermined weight of such ingredients into the flour conveying system of a modern bakery with the efficiency and economy that makes the use of such a product quite attractive. It is now apparent that while concentrated "yeast foods" can be made by simply removing the fillers and combining the functional ammonium salts and oxidant, such a product does not have sufficient storage life to be practicable or useful. Therefore, marketing of the mixture in bulk form has not been commercially feasible.